Sensors of many types are used to determine the position and/or state of all kinds of mechanisms. These sensors are particularly important when the position and/or state of such a mechanism cannot be determined without the aid of a remote sensor. Such a remote sensor must be reliable and must provide information that is readily usable. A sensor that provides reliable and readily usable data is clearly desirable, especially for applications which require high degrees of safety and efficiency.
For example, retractable landing gear used on an aircraft require a remote indicator to show the pilot that the gear are up or down, as the landing gear is normally out of view of the pilot sitting in the cockpit. It is very dangerous to land if one or more gear legs are partially extended, as collapse would almost certainly result. Conversely, if one or more gear were not fully retracted, drag and fuel consumption would be excessive and the aircraft structure could be overly stressed at high speed. Indicator systems currently in use have at most one light per landing gear which illuminates when the gear is fully down, and a warning light to show when there is a problem. Gear retraction is deduced by the position of the landing gear switch and by the extinguished indicator lights.
There are countless aircraft and other applications where it is desirable to provide an indicator system which allows a person to remotely and easily determine the status of certain equipment.
Accordingly, it is an object of the invention to provide status information from a remote location.
Another object of the present invention is to provide position and transition to position information.
A further and more particular object of the invention is to provide an indicator system which displays gear in transit (extension or retraction) information.
Another important object of the invention is to provide an indicator system which displays an indication that the gear have completed their travel to the required limits.